JPS622306Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Field of Application) The present invention relates to a mechanical pump that can be used for separate refueling of a two-stroke engine.

(Prior Art) As shown in FIGS. 1 and 2, a conventional mechanical pump is of a type in which a bottomed cylindrical rotary valve rotates, and a plunger fitted inside the rotary valve rotates and reciprocates. In Fig. 1, 1 is a bottomed cylindrical rotary valve, 2 is a plunger fitted in the rotary valve 1, 3 is a control shaft arranged perpendicular to the plunger 2, and 4 is a plunger fitted into the rotary valve 1.
is a worm gear provided on the outer periphery of the plunger 2, 5 is a lead (cylindrical end surface cam) provided on the end surface of the plunger 2, 6 is a long hole provided in the rotary valve 1, and 7 is a diametrical pin fixed to the plunger 2. , both ends of the pin 7 are engaged with the elongated hole 6. A driving worm 8 is connected to, for example, the crankshaft of the engine, and is rotatably supported within a bearing provided in the first pump housing 9', and transmits rotational force to the worm gear 4 meshing with the worm gear.

The plunger 2 receives the elasticity of the compression coil spring 10 and moves into the guide 1 of the control shaft 3 .
For example, the stroke of the plunger 2 is made variable by rotating the control shaft 3 with the lever 12 and changing the cam lift of the guide 11. 13 is a pump chamber, which includes a port (not shown) communicating with the suction port 14 and a discharge port 15' (discharge port).
has.

(Problems to be Solved by the Invention) According to the conventional structure shown in FIG. 1, the worm gear 4 is provided on the plunger 2 with a small shaft diameter, and the overhang from the bearing portion 1a is also large.
When the lead 5 rides on the guide 11, a bending moment is generated and the lead 5 is strained. Also, a rotation transmission mechanism from the plunger 2 to the rotary valve 1 is required. That is, in order to transmit rotation from the plunger 2 to the rotary valve 1 via the pin 7 and the elongated hole 6,
The backlash increases, and due to the synergistic effect with the above-mentioned twisting, the operation tends to become unsmooth and unstable, and there is a drawback that the discharge amount cannot be precisely controlled.

In another conventional example shown in FIG. 2, the pin 7 that transmits rotation from the rotary valve 1 to the plunger 2 cannot be made thicker because it is controlled by the diameter of the plunger 2 . It does not have sufficient strength to resist the friction of the lead 5, the friction between the pin 7 and the elongated hole 6, etc. This tends to cause a lot of backlash, making it impossible to accurately control the discharge amount, and also making the structure complicated.

The present invention attempts to solve the above-mentioned problems by achieving smooth operation and stable discharge amount, and by simplifying and compacting the structure.

(Means for solving the problem) A first pump housing B9' having a drive worm 8 is provided with a second pump housing B9' having an inlet port 14 and a discharge port 15'.
Tighten the pump housing 9; one end of the bottomed cylindrical rotary valve 1, which is rotatably and slidably fitted into the second pump housing 9, protrudes into the first pump housing 9'; mesh the worm gear 4 provided in the drive worm 8;
The plunger 2 is inserted into the rotary valve 1 from the end on the worm gear 4 side so as to be rotatable and slidable; between the plunger 2 and the rotary valve 1,
The plunger 2 is always urged in the direction to escape from the rotary valve 1, and the first pump housing 9'
A spring 10 is compressed and applied to the inner surface 19 of the rotary valve 1; a reed 5 consisting of a cylindrical end face cam for giving reciprocating motion is provided at the other end of the rotary valve 1; the reed 5 is connected to the control shaft at two points on its diameter. The above spring 10 is attached to the guide 11 of 3.
A control shaft 3 is provided to rotate the guide 11 to change the cam lift of the guide 11; a pump chamber 1 is provided in the rotary valve 1 between the worm gear 4 and the reed 5;
This is a mechanical pump characterized by having 3.

(Example) In FIG. 3, the same reference numerals as in FIGS. 1 and 2 indicate corresponding parts. A cylindrical rotary valve 1 fitted into a cylinder in a second pump housing 9 is integrally equipped with a worm gear 4 on the outer periphery of one end thereof, and this worm gear 4 meshes with a worm 8, and the other end of the rotary valve 1 The lead 5 provided in the control shaft 3 is elastically seated on the guide 11 of the control shaft 3 by the elasticity of the spring 10.

A plug 17 is press-fitted into the rotary valve 1, and a pump chamber 13 is formed between the plug 17 and the plunger 2.
A suction port 14' and a discharge port 15', which communicate with each other, are open. A snap spring 18 is fixed to the outer end of the plunger 2 inserted into the rotary valve 1, and the snap spring 18 and the rotary valve 1 are connected to each other.
A spring 10 is compressed between the plunger 2 and the end face of the plunger 2, so that the outer end of the plunger 2 is always pressed against the inner surface of the first pump housing 9'. This allows plunger 2
remains at a predetermined position relative to the pump housing 9'.

Next, the operation will be explained. When the engine starts and the worm 8 rotates, the rotary valve 1 rotates at a greatly reduced rotation speed, and at the same time, due to the action of the reed 5 and the guide 11, it makes two reciprocations per rotation.
Since the plunger 2 is stationary due to the elasticity of the spring 10 as described above, the rotary valve 1
During the downward stroke, the port 14' is closed by the inner wall of the second pump housing 9 and the inside of the pump chamber 13 is pressurized, and the lubricating oil in the pump chamber 13 passes through the discharge port 15' to the crank bearing of the engine. It is supplied to parts that require lubrication, such as cylinders and cylinders. When the rotary valve 1 rotates approximately 90 degrees and ascends, the port 14' communicates with the suction port 14 and lubricating oil is sucked into the pump chamber 13 (the fourth
figure). While the rotary valve 1 is rotating, the plunger 2 receives a certain amount of rotational force from the rotary valve 1 side due to friction between the plunger 2 and the rotary valve 1, but it does not need to rotate at the same speed as the rotary valve 1; It rotates gently at a rotation speed that is lower than 1.

(Effects of the invention) (a) A worm gear 4 is provided at one end of the rotary valve 1, a lead 5 is provided at the other end, and the worm gear 4 is fitted into the rotary valve 1 from the end on the side of the worm gear 4 so as to be rotatable and slidable. a plunger 2 that is always urged in the escape direction from the plunger 1 and is applied to the inner surface 19 of the first pump housing 9';
By providing the pump chamber 13 within the rotary valve 1 between the worm gear 4 and the reed 5, the interior of the worm gear 4 portion of the rotary valve 1 can be used effectively. That is, since the end of the rotary valve 1 on the worm gear 4 side can be used as a long support part for the plunger 2, which is the most important part for improving pumping accuracy, the plunger 2 is less likely to twist or rattle, resulting in a smooth Sliding and rotation are obtained. Therefore, it becomes possible to accurately control the minute amount of discharge.

Furthermore, the inside of the worm gear 4 portion of the rotary valve 1 can be used as a support for the plunger 2, and in extreme cases, as the pump chamber 13. As a result, it is easy to take a long pumping stroke, and the overall length is limited. A sufficiently long stroke can be obtained even in the case where the stroke is small, and compactness can be achieved. That is, the present invention is also effective when it is necessary to obtain sufficient pump capacity when a long pumping stroke is required or when the overall length is limited to a short length.

(b) The lead 5 consisting of the cylindrical end cam of the rotary valve 1 is connected to the guide 5 at two points on its diameter.
1, the guide 11 and the reed 5 of the rotary valve 1 can come into contact with each other over a large cross-sectional area, and there is little wear on the contact portion. Since there is little wear on the contact parts, a stable discharge amount can be obtained over a long period of time.

(c) The pump housing is divided into a first pump housing 9' having a drive worm 8 and a second pump housing 9, and the second pump housing 9 is fastened to the first pump housing 9'. Therefore, the first one on the drive worm 8 side
The pump housing 9' can be used as the main body of the engine or other auxiliary parts (for example, a water pump), and the worm 8 can be mounted on a shaft used for other purposes. Therefore, this configuration not only makes it possible to share the first pump housing 9' with other members, but also eliminates the need for a shaft equipped with a worm that is used only for driving the oil pump, which was previously required. This also makes it possible to simplify the configuration.

(d) Worm gear 4 meshing with drive worm 8
Since the plunger 2 is simply rotatably and slidably inserted into the rotary valve 1 having 2
There is no need for a motion transmission mechanism (such as a pin or a long hole) from the plunger 2 to the rotary valve 1, and the structure becomes extremely simple, and the manufacturing cost is also significantly reduced.

(e) Since the lead 5 is provided on the rotary valve 1, there is no need to provide the lead 5 on the plunger 2, material removal can be made effective, and costs can be reduced from this aspect as well.

[Brief explanation of the drawing]

1 and 2 are longitudinal sectional views showing a conventional example, FIG. 3 is a longitudinal sectional view of a mechanical pump according to the present invention, and FIG. 4 is a longitudinal sectional view when the rotary valve is raised. 1...Rotary valve, 2...Plunger, 4...Worm gear, 5...Lead, 8...
...Drive worm, 9...Second pump housing,
9'...First pump housing, 14...Suction port, 15'...Discharge port (discharge port).

Claims (1)

[Scope of utility model registration request] A second pump housing 9 having an inlet port 14 and a discharge port 15' is fastened to a first pump housing 9' having a drive worm 8; One end of the rotary valve 1 having a cylindrical bottom is projected into the first pump housing 9', and the worm gear 4 provided on the outer periphery of the protruding portion is engaged with the drive worm 8; Insert the plunger 2 so that it can rotate and slide freely from the end;
A spring 10 is compressed between the plunger 2 and the rotary valve 1, and urges the plunger 2 in a direction to constantly escape from the rotary valve 1 so as to apply it to the inner surface 19 of the first pump housing 9'; the other end of the rotary valve 1 A reed 5 consisting of a cylindrical side cam for giving reciprocating motion is provided; the reed 5 is elastically seated on the guide 11 at two points on its diameter by the spring 10; the guide 11 is rotated; A mechanical pump characterized in that a control shaft 3 is provided to change the cam lift of a guide 11; and a pump chamber 13 is provided in a rotary valve 1 between a worm gear 4 and a lead 5.